Hemodialysis is used for removing toxic wastes from the human body in cases of renal failure, and involves using an artificial kidney in conjunction with an associated machine. The patient's blood is temporarily brought outside of the body with the help of tubes and passed through at least one semipermeable membrane, which may be a group of hollow fibers, in the artificial kidney, also called a dialyzer. The semi permeable membrane separates the blood from dialysate solution. The impurities from the blood pass through the membrane and into the dialysate solutions primarily by osmotic pressures. The cleansed blood is then returned to the body. During this procedure, it may also be necessary to remove excess fluids from the body. This is accomplished by a process known as hemofiltration or ultrafiltration. In this process, I.V. quality, or sterile, replacement fluid is infused into the patient by a direct connection between the dialysate circuit and the blood circuit (by-passing the dialyzer) and an equal amount of fluid is removed from the patient by taking the fluid off through the dialyzer and discarding it. Further, an additional amount of fluid in the form of ultrafiltrate may be optionally removed to obtain a net removal of fluid from a fluid-overloaded patient. The amount of ultrafiltrate removed from the patient is normally controlled by pressure across the semipermeable membrane. This transmembrane pressure is the result of the differential between the blood pressure and the pressure which exists on the dialysate side of the membrane.
Hemodialysis procedures using standard equipment tend to be cumbersome as well as costly, in addition to requiring the patient to be bound to a dialysis center for long durations. Conventional systems are also less reliable because of the necessity of using myriad of tubes comprising the fluid circuits of the purification systems, thus increasing the risks of leakage and breakage. Besides being difficult to transport due to their large size, conventional hemodialysis machines also suffer from a lack of flexibility. For example, sorbent based hemodialysis procedures have a particular set of hardware requirements that are not shared by the hemofiltration process. Thus, it would be beneficial to have common hardware components such as the pumping system, which can be used such that the dialysis system can be operated in hemofiltration as well as hemodialysis modes.
Additionally, there is a need for a portable system that can effectively provide the functionality of a dialysis system in a safe, cost-effective, and reliable manner. In particular, there is a need for a compact dialysis fluid reservoir system that can satisfy the fluid delivery requirements of a dialysis procedure while integrating therein various other critical functions, such as fluid heating, fluid measurement and monitoring, and leak detection.